


Heart of the Ocean

by KylaSheaHarkins



Category: Shingeki no Kyojin | Attack on Titan
Genre: Carla and Grisha are dead, Chef! Jean, Crab! Hanji, Disney AU, Eel! Nile, Eren is a fucking adorable prince, Eventual Smut, Evil Sea Witch! Erwin, Half-Octopus! Erwin, Harlequin Tusk! Petra, Human! Eren, I just don't know where yet, Kuchel is dead, Levi and Mikasa love each other SO MUCH, Levi calls Mikasa 'Mika' and it's ADORABLE OKAY, Levi sings, Levi-centric (Shingeki no Kyojin), Levi/Eren Yeager-centric, Little Mermaid AU, M/M, Mermaid! Levi, Mermaid! Prince! Levi, Mermaids, Mikasa and Levi are siblings, Mute! Levi, Nile is a fucking eel lmao, Oh yeah Armin is in here too, Prince! Eren, S W I T C H I N G, Slow Build, Slow Burn, Switching, Top! Eren Jaeger, bottom! Eren, bottom! levi, ereri, everyone's a fucking fish, fuck nile, levi pov, mermaid au, multi-chapter, omg he SINGS AND SMILES AND IS HAPPY, riren - Freeform, the OCEAN!, these tags tho lmao, top! levi
Language: English
Status: In-Progress
Published: 2016-10-04
Updated: 2016-10-22
Packaged: 2018-08-19 11:46:53
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,993
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8205347
Author URL: https://archiveofourown.org/users/KylaSheaHarkins/pseuds/KylaSheaHarkins
Summary: Little Mermaid AU. Merman Levi is absolutely captivated by a certain teal-eyed human and will do anything in his power, or someone else's power to be with him. Sticks to the movie quite a bit, but I've changed and added a few things. I suck at summaries, I'm sorry. Multi-chapter, work in progress.





	1. Chapter 1

**Author's Note:**

> I became inspired when I saw the artwork of levi.heishichou.chiieru (IG). The art is just SO GOOD and I got SO EXCITED about it I just had to write it. Should I be updating "Our Reluctant Hero" or "You Will Always Be My Thunder"? Probably. But I just, my dudes I'm so excited about this.

I love this feeling. The water is so much cooler, the lower down I swim, and I know I’m going to be rewarded for my efforts. I swim around a small alcove and it comes into my sight, the _Queen Anne_.

 

“Levi! Wait up!”, I turn and catch sight of Petra. We’ve been friends for years, but I still sometimes forget that my strong mer-fin makes me swim a lot faster than hers. She’s not a mermaid, just a Harlequin Tusk. I wait as she catches up, then hold my arms out to her, which she swims into and nestles down.

 

“I want to hurry and look, you know father’s expecting me back soon.”

 

I close my arms around her and push off, gliding my fin back and forth, towards the grand ship. Once I get to the top deck, I release Petra and go below, knowing she will follow or go look around on her own. I look around at the seaweed covered barrels, the floorboards are broken and missing in some spots, allowing me to see the sea floor below.

 

Nothing.

 

I swim back up, and pry open the door into what I can only guess as the Captain’s cabin. Some trinkets are scattered about, and I rummage through the chest hidden behind the desk. I was self-taught in the language of human’s above, and I had read in one of my scavenged books that the _Queen Anne_ was used by pirates.

 

I find the chest has a false bottom, and quickly pull it out. I gasped as I picked up the necklace, watching it shimmer in the glowing light reflecting from the sun. I idly wonder how much more it would sparkle in the sun.

 

The necklace is heavy. Laced with a thick silver chain, the only charm it has is a giant gem, cut into the shape of a heart. The gem has an odd color, similar to the clear blue-green waters off the coast of a human country called Italy. I place it in my mouth and gently give it a hard bite, guessing it was diamond. I see the box it was placed in, laying in the bottom of the trunk, I pick it up and a piece of paper falls out. It’s a miracle the paper is still intact, even more so that the writing is still visible and legible. I sound it out in my head.

 

_H-hee. No. H-heart of? Heart of th-ee o-o... Ocean? Heart of the Ocean? Yes! Heart of the Ocean!_

 

Huh, funny name for a necklace.

 

Whatever, humans can be weird.

 

I begin to hum to myself as I begin looking at the books on the bookshelf, searching for any books that might be salvageable. I placed the necklace in a bag I kept around my neck.

 

“Levi! LEVI!” Petra swam through the door, out of breath, but fear in her eyes.

 

That’s when I smelled it, smelled _him_.

 

I held her in my arms and shushed her, swimming backwards until my body was hidden in the shadows and my back was completely flat against the wall.

 

Erwin, the sea witch.

 

I saw him swim around outside, looking this way and that, as if confused about where he was. I won’t deny he’s handsome as hell. Silky blond hair that flows in the water, weightless. Piercing blue eyes, a symmetrical face. A chiseled upper body. We were similar, us mer-folk and he. But his lower half was that of an octopus, with eight, strong tentacles. I see his two eels approach, Nile and Thorn I think they’re names are.

 

I’m barely breathing, not wanting to bring attention to myself. I’m a fast swimmer, but if Erwin gets a hold of me, there’s no way I can fight him off.

 

What is he doing all the way out here? He’s just swimming there, like he’s waiting for something.

 

A current shifts, and I watch as a book begins to slid off the shelf. I close my eyes, praying for it to make only a soft sound as it lands, but as always, odds are against me and it lands with a thud. I open my eyes and I see those terrifying blue eyes staring back at me, and I know that he knows I’m here. I don’t even think, I just begin to swim. Holding Petra close against my chest, I swim as fast as my mer-fin can kick. I don’t look back, knowing I would have to slow down to do so. I’m not even sure if he’s chasing me, I just swim until my lungs are burning and I feel my eyes begin to droop. I didn’t realize how far I had swam from the palace. I turn around, seeing nothing but the vast blue of the ocean behind me. I swim more slowly then, catching my breath. 

 

It came into view then, standing proud in all it’s grandeur.

 

I release Petra then, and she thanked me, telling me she would meet me at the secret place later. I went ahead without her. I swam around the back end of the palace, and went low. I swam under some rocks, into what could be considered a small trench, and I arrived at my secret cove. I moved the large rock blocking the entrance, and went inside. I finally allowed myself to rest, laying flat on the sandy floor. I bring the necklace out of the bag and hold it up to the light, watching the reflections of light dance across the small room and my own skin.

 

It’s beautiful.

 

I begin to hum again, now that I’m out of danger I allow my body to completely relax. My humming turns into murmurs of words, and soon I’m bellowing out songs I sing with my sister, Mikasa.

 

“ _There were three ravens sat on a tree,_

_There were as black as they might be._

_With a down, derrie, derrie, derrie, downe, downe, downe._

_The one of them said to his mate,_

_Where shall we our breakfast take?_

_Downe in yonder green field,_

_There lies a Knight slain under his shield._ ”

 

I didn’t hear my makeshift door move, I was so entranced by the song our mother taught us. It was a dark tale, but I loved it so much. And then a familiar voice joined me.

 

“ _His hounds they lie downe at his feete,_

_So well the can their Master keepe,_

_His hawkes they fly so eagerly,_

_There’s no fowle dare him come nie._ ”

 

We finish the song, smiling at each other. Mikasa lays beside me, taking my hand. Ever since our mother passed away, she has acted as a replacement for me, even though she isn’t but a couple years older than I am.

 

Kenny isn’t our real father, but we call him our father anyway. He adopted us, as is the custom when a family member dies. As he is our mother’s brother, the duty fell to him. He didn’t mind, he can be a fierce ruler, but he’s always been kind (and strict) to Mikasa and I.

 

“Father was looking for you. What did you find today?”

 

Our father didn’t know about my secret adventures to find human treasures. He hates humans, because they are the reason our mother is dead. I hold up the necklace, showing it to Mikasa. She lays there and watches it sparkle in the reflecting sun. She says to me, “It’s so pretty.”

 

“I know. I found a note with it, it’s called the Heart of the Ocean”, I tell her.

 

She looks at it for a few more minutes, saying quietly, “The name suits it well. I’ve seen waters this color along the coast lines of Italy, but more so over near the Caribbean Isles.”

 

I say nothing, handing her the necklace and swimming to an old ‘world map’ I found in a sunken ship. I have it carefully propped up against some books, and held down with what humans call ‘paper weights’. I point my finger to the ocean next to the country called “England”, that’s where we live, about twelve hours out from a small, but lively port town. I’ve never been, but Mikasa has. She traveled a lot after mother died. I run my fingers along the length of the map until I reach a place called ‘new world’ and go down until I spot ‘Caribbean’.

 

“How long did it take you to get there, Mika?”

 

“Hm? Oh, the Caribbean? A year, give or take. That was my longest trip. The water was absolutely beautiful, and it was so warm. If you’re ever up for it when you’re older, I’ll take you.” She gives me a smile as she says this. I really wish she would smile more, she looks just like mother when she does

 

. I swim to her, and she releases the necklace. I place it in a ‘jewel box’ and swim back to her, grabbing her hand.

 

“Come on. Let’s go see Kenny before he comes looking for me.” We swim out and I slide the rock back into place.

 

I think back to the necklace, the gem. It really is such a beautiful color.


	2. Chapter 2

**Summary for the Chapter:**

> It's short, but it gives a little background and some conversation with Kenny.

“Where have you been Levi?”

Levi and Mikasa had entered the large throne room, where Kenny sat with Hanji by his side. They swam up to where their uncle sat, and Levi began to explain how he had found an amazing bed of sea blooms and had accidentally fallen asleep. He told the king that he could as Petra if he wanted, she would vouch for his whereabouts. 

“That’s fine then. I worry about you, Lee. I know you’ve got a dangerous fascination with those vermin above. You know what they can do to our kind, what they did to your mother,” Kenny tells him. Levi’s heart aches at the childhood nickname his mother often called him. His uncle and Mikasa sometimes slipped and called him by it every so often, not that he minded, it just brought on painful memories. 

“Yes, sir. I know they’re dangerous. It’s not even them I’m interested in really, it’s just their stuff.”

Levi had let this sliver of information slip past his lips on purpose, gouging his uncle’s reaction.

“Yes, well. You want to learn more and more, and eventually go topside to see it for yourself. Lee, you're a smart boy. Your mother was a smart woman, too. And yet, she was still drawn to that other world, and now look where she is. I love you and Mikasa so much, you’re the only family I have left. I just don’t want to lose you.”

Levi and Mikasa spared a glance as Kenny finished his speech. He wasn’t an unkind man, he just had a few strict rules that he needed to be followed. He wasn’t unfair in his ruling, because he had seen so much of the world, and was knowledgeable about the dangers of it. Levi loved his uncle, but the pull to the world above was just so strong. 

He had never been higher than a few feet below the surface, low enough that he couldn’t feel the suns heating rays. What stopped him was the fear; the fear that someone would see him, the fear of being caught and killed like his mother, the fear of leaving Mika behind. 

In his nineteen years, he had never felt the direct heat of the sun on his skin.

He decided that it was time to change that.

**Notes for the Chapter:**

> Also, let's just pretend "Sea Blooms" are a type of flower looking thing that grows in the ocean.


	3. Chapter 3

I can feel my heart pounding in my chest. The closer I get to the surface, the more it seems like it’s going to burst from my rib cage.

I’m about four hours away from the castle, I wanted to make sure no one saw me when I swam to the surface. I kicked my fin faster, anxious to break through the barrier between me and the human world.

It was more beautiful than I ever imagined. The paintings and pictures in books couldn’t do it justice. The sun. It was so _warm_. The heat pierced my skin, warming my upper body that was sticking up out of the water. The sky was a beautiful blue with puffy white clouds, I could almost make out shapes in them. I laid back, letting my full body lay on the surface of the water, letting the waves roll my body. It smelled salty up here, but it was calming.

_-creak-_

I shoot up, looking around.

My eyes widened at the not-too-distant ship, sailing right for me.

I quickly dived under water, breathing erratic. I was sure no one had saw me, I swam back up, eyes barely breaking the surface, watching the huge ship sailing in the wind. It was gorgeous, and it’s name on the side said _Poseidon_. I wasn’t aware that humans knew of our ancestor, the God of the ocean, Poseidon. My royal bloodline was supposedly a direct descendant from him, but I didn’t know for sure nor care.

I was feeling brave today, I decided I wanted a closer look.

I swam up to the side of the ship, waiting until I was sure the coast was clear and no one was near the edge. A wave helped me push myself up, I grabbed a hold of some sort of wooden decoration on the side. It provided just enough room to allow me to lay on my side, peeking under the side boards and watching the humans up close.

There was so much going on!

There were men walking back and forth, carrying various things like ropes and hooks. There was a blond man steering the ship, who’s eyes eerily remind me of Erwin’s. I shook my head, scolding myself. To even think of the sea witch could cause bad luck.

Suddenly the men had their attention on a door located under where the wheel was. They did an odd solute, with one arm bent behind their backs and the other in a fist over their hearts. I looked around curiously, wondering what could cause the human’s to behave so strangely.

Out of the door stepped out the most beautiful man I had ever seen.

Not to say I had seen a lot of humans, of course. But mer-folk were meant to be beautiful by nature. A trait inherited from our Siren ancestors, which I also apparently inherited my ability to sing from. I believed the beauty part about Mikasa, but I thought of myself as average looking at best.

I watched as the blond man motioned for a boy with shaved hair to take the wheel. He walked down to the man, the Captain I assumed. Behind the beautiful man came a four legged animal. I had read that humans keep pets, but I couldn’t remember what this was called. It was furry, with tan legs, stomach, and face, and black fur from the top of it’s head to it’s tail, which was bushy and wagging fiercely when the blond reached down to pet it.

My eyes flicked back to the beautiful man. His skin was a beautiful tan color, hair brown and messy on his head. His shirt was opened and I could see the defined abs going down his stomach. His face was symmetrical and he had perfect lips.

But his eyes.

They were the same color as the necklace I had found, the _Heart of the Ocean_.

I couldn’t stop staring.

“Alright! As you all know, it’s Prince Eren’s birthday!”

The blond spoke, gaining cheers from the crew that stood around them.

“Happy twentieth birthday, Eren. I have a surprise for you. Are you ready?”

I watched, mesmerized as a slight blush crawled across the beautiful man’s, Eren’s, face. I think my heart might have stopped when he smiled at his blond friend.

“If you’ve found me another prince or princess to marry, I’ll toss you overboard Armin.”

My breath caught in my throat at the sound of his voice. It was melodic, deep and throaty, and he wasn’t even singing! I didn’t want to even blink, afraid I might miss a moment of seeing this beautiful creature.

Eren.

Armin walked over to a large, covered object, pulling it away to reveal a stone figure of Eren himself. It captured him beautifully, but the grey color of the stone could never do his beauty justice.

I stifled a giggle as Eren grimaced, but smirked at the blond boy, Armin he had called him. “No wonder people think I’m an arrogant prince. The paintings of me, my face printed on money, and now this life-sized statue. What am I going to do with you, Armin?”

Eren faced west then, and I turned with him, seeing the sun was dipping low in the horizon. It was getting dark, but I didn’t want to leave, couldn’t.

I stayed, watching Eren well past sunset. His crew played instruments and some danced and sang songs. Some songs I even knew, from my mother singing them. I began to hum quietly when they were singing a particular favorite of mine. Eyes always on Eren, he just nodded his head to the music, sometimes talking to others, but mostly keeping to himself.

The animal that stayed by Eren’s side looked over to where I was sitting. It must have had exceptional hearing, and I didn’t notice until it began to approach me. It whined, high and nudged Eren’s leg. Eren asked the creature what was wrong, and began to follow it to the side of the ship, straight to me.

I panicked, I dove off.

“Levi!”

I could recognize that high pitched squeal anywhere.

I turned slowly, eyeing Hanji with annoyance.

“What?”

“We’ve been searching for you! You’ve been gone for hours! What have you been doing? Are you alright?” She was firing questions faster than I was able to answer. I put a hand up, ceasing her incessant questioning.

“I was...people watching.” Hanji may have been Kenny’s right hand, but she and I had been friends for a long time. I knew she could keep a secret if needed.

Hanji stared at me. “You know how dangerous humans are, Levi. What they’ve done to your kind, to your mother...” She didn’t finish. Of course I knew what humans had done to my mother, I was there. I had watched. Even as she screamed at me to run, I was too frozen in fear to move. Mikasa had swam away to get Kenny, hoping he would be able to help somehow.

 

* * *

 

 

_“Come on my little pearls. I want to show you something amazing!”, Kuchel was swimming in front of her two young children. Levi was only eight, and Mikasa eleven. “Mama we’ve been swimming for hours, my fin is getting tired.”, Levi complained, Mikasa nodded in agreement._

_“I know little ones, but we’re almost there, I promise.”_

_They were following a large shadow. It’s size amazed yet terrified the mer-children, but they trusted their mother to keep them safe._

_They swam for about another hour, when Kuchel turned to them. “We’re going to the surface, stay near me and do exactly as I say. Understood?” The two young children nodded, eyes widening as they swam closer and closer to the surface._

_The shadow had stopped and dropped something heavy down. It dug into the sand on the ocean floor._

_“You two wait right here, I’m going to make sure it’s safe.”_

_They watched as their mother broke the surface, turning this way and that._

_Mikasa and Levi began to play the clapping game their Uncle had showed them, when they heard a blood curdling scream from above. They jerked their heads up, eyes widening._

_They’re mother was hovering above them, screaming at them to run, her hand on her shoulder, blood spilling from it._

_“Levi! Come on! We have to get Uncle Kenny!”, Mikasa was pulling his arm, but he was frozen, unable to move. He could only stare at his mother as she turned, swimming back to the surface. Other figures had appeared in the water, and were now surrounding her._

_Mikasa huffed “Please stay here, Levi. Don’t go to Mama!”, releasing Levi and swimming away, kicking as fast as she could._

_Kuchel tried to swim below, tried to swim to Levi, but something caught her by the hair and pulled her back up. He watched hands appear under the water from the shadows, wielding strange blades, and he watched as the silver blades disappeared inside his mother’s body._

_Kuchel’s eyes, the same stormy grey as Levi’s own, stared down at her only son. Levi watched the light leave them, watched her stop struggling, stop breathing._

_Watched her body be dragged to the large shadow by the smaller ones, and finally, watched her body disappear forever._

_Levi sank down until he was on the ocean floor. He swam under a small grotto, putting his face into his hands, and sobbed for his mother. He called for her until his throat went hoarse._

_“What an absolute shame.”_

_Levi’s head jerked up at the deep voice._

_His eyes bore into light blue eyes. This creature couldn’t have been much older than Mikasa, maybe around seventeen or so. Levi let his eyes wonder down the torso, like his own, but instead of a mer-tail, this creature had tentacles like that of an octopus._

_The creature swam closer to him, wrapping his tentacles around Levi’s tail, wrists, and neck. He didn’t even try to fight back, just let his body be dragged to the strange creature._

_He should have felt fear, but he couldn’t feel anything._

_“What a beautiful boy you’re becoming Prince Levi. You’ll become a gorgeous merman one day.” A tentacle slid up his tail, over the slit in the front._

_His mother and Uncle had told him this was only supposed to be touched by the person you loved, your mate. And he was only eight! This creature had no right to touch him there!_

_He squirmed, body finally responding the way it was supposed to._

_“Who are you!? Let me go! Please!”_

_The creature chuckled darkly, bringing Levi closer to him. He licked over the gills on Levi’s neck, “My name is Erwin. I am the sea witch your people fear so much.”_

_Levi shuddered at the contact, because mer-folk’s gills were sensitive. He continued to squirm around, trying to free himself. It was then he heard the distant calling of his name, he recognized his uncle’s voice._

_“Uncle Kenny! Help me-mph”, a tentacle thrust into his mouth, and he gagged but couldn’t maneuver away from the appendage._

_“Not a word, little one. Or I can kill you in an instant.” Levi nodded, and the tentacle was removed from his mouth._

_“I’m sure we’ll meet again, beautiful prince.”_

_Levi shuddered in fear at the darkness in Erwin’s voice. The tentacles were slowly removed from his body, and he watched Erwin disappear deeper into the sea cave until he could see nothing but his piercing blue eyes._

_He swam up quickly, running into Kenny’s chest, hugging him tightly and screaming for his mother._

_Kenny went to the surface, after swearing that nothing would happen to him, and could find no trace of Kuchel anywhere._

_The three of them swam back to the palace in silence. Levi between the two, holding each of their hands._

_The kingdom mourned for months, even after Kenny was crowned King._

 

* * *

 

 

I never told anyone about my encounter with Erwin. I had a couple of more run-ins with him over the years, but I was always able to swim away before he got his slimy tentacles back around me.

I completely understand my uncle’s hatred for humans. I should hate them too, after everything I witnessed, but something kept drawing me to them.

And then I saw Eren.

I know in my heart, I want to be by his side.

I’ll do anything to be able to stand by his side.

**Notes for the Chapter:**

> I live off of Kudos and Comments, feed me Reader-Chan.
> 
> Also, yeah. Eren has a fucking German Shepherd lmao. It's name is Jaeger

**Author's Note:**

> Please leave kudos and I live off comments, feed them to me.
> 
> ALSO!: I fucking love Erwin. I truly and honestly do. He is my baby boy, my precious sunshine. But I needed a villain and Erwin is just so calculating and shit, he was perfect. Also, I know I called Erwin a sea witch and witch typically means female but fuck that. He's a badass, gorgeous sea witch.
> 
> Follow me on Tumblr: http://kylasheaharkins.tumblr.com/
> 
> I'm tracking this story on tumblr. Tagged fic: heart of the ocean


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